Method of irradiating substances with active rays



March z, 1937.

E. c. BERNDT ET AL. 2,072,416v

METHOD OF IRRADIATING SUBSTANCES WITH ACTIVE RAYS Original Filed Jan. 16, 1933 5 Sheets-SheetV l n v 5f www e, maw/L 5MM m.

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March 2, 1937. E. c. BERNDT ET Al. 2,072,416

METHOD OF IRRDIATING SUBSTANCES WITH AC-TIVE RYS Original-Filed Jan. 16, -1933 5 Sheets-Sheet 2 I @Wam/rm I l @Awa/u) G. @www0/E,

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YM W m March 2, 1937. E. c. BERNDT ET Al.

METHOD OF'IRRADIATING SUBSTANCES WITH ACTIVE RAYS Orlglnal Flled Jan 16, 19253 3 Sheets-Sheet 3 BY MX Patented Mer. 2, 1931 2.012.416 Y rananrs'rmo Yssuns'rauorzs METHOD F PATENT orifice WITH' ACTIVE RA Edward C. Berndt, Norwalk, and HarryM. Creign.

ton, East Norwalk. Conn.. asalgnora to B. U. V. Engineering Corporation, South Norwalk. Conn., a corporation of Delaware Application January 10. i938,

Renewed March 22.

i. 19 Claima- I'his invention relates to the method bf treating or irradiating substances with active rays, such as ultra-violet rays, to impart beneficial properties or effects thereto, and more particur, larly to the treatment of such substances which are susceptible of being injured during, or by the treatment thereof, with such active rays. Our method of treatment makes itpossible to obtain the beneficial effects without detrimental effects,

in or to obtain the maximum beneficial effects with little, if any, detrimental effects, in a s impler, more eiilcient, and reliable manner than has heretofore been obtained by workers in this field.

It is well known that active rays, such as ultram violct rays, have various effects on diiferent substances. For example, these raysy will kill balcteria and also impart to' certain substances a property which is now called vitamin D. Active rays will also stimulate bacteria rather than kill 0 them if the treatment is mild enough. Moref over, it has been found desirable to use these rays for the sterilization and/or activation oft 30 cases the method to be hereinafter described is also applicable. There'are also other reasons for the treatment of vsubstances with active rays such as to produce beneficial chemical reactions or to irradiate oils'and petroleum products to impart to them healing effects -or other properties. However, the use of. active rays may result in producing both detrimental and beneficial effects, and we have found it is highly important for the irradiation of a substance to be accurately controlled to produce the result desired.

An example of the importance of this control may best be illustrated in the consideration of the irradiation of milk. We know that the germs which infect and propagate in milk can be destroyed with ultra-violet rays, We further know these rays will activate or produce vita-l min D in milk when it is irradiated. We also know that certain degrees of over-irradiation of portions of the milk, or particles therein. will change the taste, odor and other properties of the milk to such an extent that it may be impossible or actually dangerous to use it for human food. Hence, in theiirradiation of' milk it lis highly important to accurately control the acti- 55 vation thereof in imparting thereto or inducing seran No. osano' `uns (ci. sir-1s) I a vitaminD effect therein or in the thereof to sterilize the same, regardless ofthe irradiation degree of the result sought if the milk is to be ,know, come into commercial use. This same holds true of other substances which are relatively opaque to ultra-violet rays. We have therefore developed a process or method of irradiation whereby the irradiation can be accurately controlled, and thus make possible the use of these active rays for both sterilization and activation and the many other purposes outlined above.

vThis' application is a continuation in' part of our patent application entitled Active ray treating devices, filed January 2, 1930, and serially numbered 418,027, Patent No. 2,024,207, granted December-17, 1935. i

Accordingly, an object of our invention is to provide a process for treating substances' with active rays, which process effectively activates all portions of the substance without depending upon the accuracy of personal supervision to activate the substance uniformly. A further object of the invention is to provide a process of the above character in which the time of exposure of all portions of a substance is accurately controlled and regulated and enable one to design a device with which substances may be more efficiently treated without the aid of personal supervision.

A' further object of the invention is to provide a process for effectively activating or .treating substances of opaque'or semi-opaque character, as well as'substances bearing solids in suspension. A further object of this invention is -to provide a method of irradiating substances whereby the beneficial effects obtainable can be produced with a greater factor of safety against incidentally producing detrimental effects at the time of such treatment.

A further 'object is to provide a method of irradiating a substance wherein the maximum eifectiveness of a given amount of radiant or irradiating a substance wherein maximum beneficial effects desired and provide a safety factor against the production of detrimental enects.

A further object is to provide a method of irradiating a substance wherein maximum beneilcial effects can be produced with minimum detrimental effects; or a lesser degree of the beneficial effects, if desired, with a proportionately larger safety facwr against producing detrimental effects.

- An important object is to provide a method 6 of' irradiating milk to produce a high percentage ofthe potential amount of vitamin D effect in the milk without detrimental effects. such for example. as producing an unpleasant taste or odor therein.

A further object is to provide a method of irradiating milk to reduce the bacterial content to a safe limit and also to produce the vitamin D effect therein at the same time and cause only negligible detrimental eifectsif any. l A further object is to provide a method of irradiating milk powderto activate the same for the purposes above set forth. I

A further object is to provide a method of irradiating'orange juice and other fruit juices to the reduce the bacteria. fermentation organisms or other organisms to a safe limit thus preventing fermentation or spoilage when properly sealed and stored in a suitable container and to simultaneously add vitamin D to said '25 juices.

A further object is to provide a method of irradiating orange Juice to llrill bacteria and inactivate enzymes. A

A further object of the method is to control the amount of ray energy acting upon different portions of the substance. and thereby control the results obtained, irrespective of whether the whole range of active ray energy available from a source of active rays is used, or rays of certain wave lengths selected from said\range.

`A further object of our invention is to provide a method of irradiating a substance with active ray energy whereby one is able to forecast the results to be obtained, when undefined 0 fractional portions ofthe substance to be treated are successively irradiated.

A further object of our invention is to produce by irradiation with active rays a milk product which has been sterilized to a safe degree and 46 also which has had imparted to it anti-racisme tainable by applying the same amount of energy vin a single treatment.

Another object is to provide a method of irradiation wherein the relation between the mounts of irradiation received by differentA portions of the substance can becomputed.

Another object is to provide a method of utilining high intensity active rays in the irradiation of substances which have heretofore been damaged by the use of such rays in the treatient thereof.

Another object is to provide a method of irra- -m diation which permits the use `of the more effective short active rays so as to safely utilize this energy when irradiating substances which are susceptible to detrimental elects.

Other objects of our invention will become uapparenttothoseskilledintheartfromthe amano detailed description taken in connection with the accompanying drawings, in which.

Fig. l is a view in vertical section, taken through the axis of a device for treating substances with ultra-violet rays, such devices being constructed in accordance with the present invention. f 1 Fig. 2 is a view in end elevation, partly broken away and in section, showing the device of Fig. l.

Fig. 3 is a view in section, taken transverse to the axis of a device constructed in a modified manner but embodying the principles of the present invention.

Fig. 4 is a view similar to Fig'. 3, showing. a

further modified device in which the path of the substance being treated lies adjacent the enclosure for the source of active rays over an ex. tended portion thereof.

Referring to the drawings in detail, and first to the construction illustrated in Figs. l and 2 thereof, reference numeral i designates a cylindrical chamber having a peripheral cylindrical wail 2 and end walls I and I. Openings I3 and It afford a means for introducing a substance into the chamber and effecting the withdrawal of the substance therefrom. a "supplemental wall 32 is carried by the wall l, being secured within an annular recess l', formed upon the outer surface of the wall I. Cylindrical bores `l are formed in the wall 3-and supplemental wall 32, these bores being adapted to receive a cylindrical tube B of Vquartz er other suitable material.. Annular recesses 8, formed in the wall 3 and 32 receive annular packing 3, these packings beingvsecured in position by glands '4 III in an obvious manner. The cylindrical enclosure l is of such size as to afford a degree of clearance between the outer portion thereof and the bores 1, thus providing a type of cooperative relationship between the*l enclosure `and basis of a separate application Serial No. f

336,807, filed February l, 1929, Patent No.

2,000,377, granted May 7, 1935, further description thereof is believed to be unnecessary. It will thus be seen that the flow of fluid. or substance to be treated, is restricted by the bafiies and the substance is thus coursed through the chamber I in a circuitous route repeatedly coming into close proximity with the enclosure 5.

The foregoing description is directed to a structure which provides an enclosed chamber I and a chamber .8 within the cylindrical closure I. It is frequently desirable to provide a means for selecting the radiation from the source of active rays in addition to effecting the cooling of the packingscarrying the tube I5. Such selective irradiation may be effected by using different solutions of filtering substances in the cooling medium, so as to adapt said medium for simultaneous cooli-ng and filtering. For example, solutions of copper sulphate and lead acetate may be used. Asecond enclosure I6 is therefore provided within which a mercury vapor lamp I1 or other source of active rays is the l the outer portion of the supporting member to Va. gland 2l.

receive packing 24. I'his packing supports the tube Il and is secured in position by meam of The tube il is flared outwardlyat 28 and is formed with a reversely extending cylindrical portion 21 which is engaged by the packing 24. The reentrant structure at the end of tube Il thus affords a chamber between the packing 24 and the'source of active rays i1. Within this chamber a suitable fluid may new to effect the cooling of the Joint or to obstruct the flow-of the long rays of the 'I'he other end of the enclosure I4v is mounted in a supporting member 2l which is similar in construction to Ithe supporting member 2i. lThe cylindrical ilange 2l is mounted over a corresponding flange 30 on the supplemental walt/I2, packing Il affording the desired joint between the supporting member 28 and the supplemental wall 32. The .supporting member 2l is secured to the supplemental wall by means of bolts I3 tube 42 to treat the substance i'iowing between the bames. There does noty result'from the above treatment any over-treatment of the surface ofthe substance in order to provide proper treatment of the entire substance.

With reference to-1?ig.'4. there is -shown -a construction in which a fewer number of baffles vis used. These baffles are shown ati and are '42. The foregoing structure causes portions of in a well known fashion and carries packing 24 and gland 25 in a manner/similar to the corresponding elements described in connection with the` mounting of the other encof the tube IB.

the substance treated to be exposed to the inuenceof the active rays over a relatively extended portion of the enclosure 48.

Our method relates to the irradiation of substances capable of having beneficial or detrimental effects imparted thereto and comprises treating` such a substance withl a number of short intermittent exposures to radiant energy emanating from one or more sources or stages of active rays, no one of said exposures being sumcient to give the whole body of the substance the pipe i4, carry away the substance 'and prevent stagnant pockets being formed in such chamber in which portions of thesubstance y may lle.

gsupplemental chambers Il and l1 may be formedon the cylindrical housing to enclose the source of active rays and the specic structural characteristics of the device, apart from the elementsdescribed, may conform to the usual practice in the art.

With reference to Fig. 3, a modified device is shown for treating a substance in a comparatively thin nlm with the desired` active rays. Where the substance is opaque or partially opaque, it is necessary, c scribed, to treat all portions thereof uniformly. It is contemplated to effect the successive treating of portions of substances of this character,

L such treated vportions being mixed with untreated portions between the successive treating steps in order that the resulting process provides" a substance which is relatively uniformly treated. Thus, in Fig. 3, a container 3l, shown as cylindrical, is provided with bailies 39, disposed radially within the container and extending inwardly from the outer wall thereof. A series of v rial, is disposed axially of the housing in contact with the inner ends of baiiies 40.' Within this tube a source'jof ultra-violet rays 4I is mountedr so that rays therefrom are directed-through the the amount of treatment necessary to produce the ultimate desired beneficial results or effects, and mixing the substance between exposures, such that said mixingsl take place away from the action of the rays to permit one to control the distribution and amount of treatment'received by the substance. The proper combination of the time of each exposure or amount of treatment and the number of exposures will give a much better result than that obtained if the same total time of treatment were given without regard to the amount of each exposure: VlThe number of treatments to be given depends on f the layer thickness used, the time limits of ex- -eil'ects that may be tolerated.

To practice our method'it is necessary to unl derstand two important principles thereof,

namely, first, the minimum total time of exare produced therein. -Wlththis understanding l our invention, in one of its broad aspects, comprises exposing'a substance to the influence of active rays of suifxicient effectiveness and for such duration as to give the same a fractional treatment and to impart beneficial effects thereto but for a duration insufficient to ,impart undesirable effects thereto, mixing said substance after such fractional treatment, and th'en alternately repeating this cycle until the desired beneficial enects'throughout the substance have been attained. these repetitions being less than that required to impart detrimental effects I`thereto.l Thelayer thickness used for the treatment will depend, among other things, upon the Y character of the substance itself. A clear knowledge of this method, as hereinafter set forth, will indicate what layer thickness should be used in each individual irradiating case.

percentage of the potential vitamin D effect,

which isbeneiicial, and at the same time destroy vitamins naturally present in the milk which may be just as important or even more important than vitamin D. Also. one may injure the taste or odor of the milk to such an extent that the milk cannot be used for human consumption, or it is said one may destroy a large portion of the vitamin `D previously produced, all of which are detrimental eifects caused by the treatment'.

We have also found that it takes a lesser amount of treatment to produce vitamin D in milk than it does to produce changes in the taste or odor of the milk. Indeed, we have found. as will be hereinafter explained, that the time of exposure necessary to produce the vitamin D eifect is much shorter than the times mentioned by other workers in the literature on the subject. Some workers report times of exposure varying from eight seconds up to several minutes and even hours. We have in our experiments produced the vitamin D effect in milk with an exposure which was about one twentieth (1/20th) of a second, and in some cases we have produced the eifect with even a shorter time of exposure. We have also foundfthat some types of bacteria are killed with an exposure of about one two-hundredth (1/200th) of a second or even less, while working at a distance of one and one quarter inches from a ray source, yas will be hereinafter described. We have also found that'the amount of irradiation required te kill harmful germs in milk is less than the amount of irradiation necessary to cause a By extensive experimentation we have discovered certain general rules of treating which are readily adapted, to commercial treatment of various substances capable of having beneiicial or detrimental eifects imparted thereto. For example, we have found it is well to irradiate milk by moving it through-,the field of ultraviolet rays having an intensity in proportion to the concentration of the element to be affected' by the treatment. We have treated milk with rays of various intensities and have found that goed results, for example. 'are obtainable at a distance of about one and one quarter inches from a source of ultra-violet rays, which was a 220 volt hot anode type direct current quartz mercury vapor arc. The arc length in this case was six inches and the diameter ofthe luminous tube iive eighths of an inch, and the operating volts 170, and the `current 3.5'amperes and 'it is removed from the action of the rays.

aovaue Cray may be use. The intensity and wave lengths produced under the condition outlined gave excellent irradiating results when irradiating milk with our method.

We have treated some suchv substances by keeping them comparatively cold; others we have treated while comparatively hot. Our method is one which can bel applied to various substances, and the temperatures therefore may vary with the problem at hand. It will be understood that our method pertains to the control of the amount of irradiation received by different porticns of the substance, whether` or not the substance is heated orcooled during the treatment. However, changes in the temperature of some substances will change the limits of the period of irradiation or the amounts of treatment to be considered.

In the consideration oi' the application of our method it should be remembered that active rays such as ultra-violet rays of different wave lengths have dierent penetrating qualities in a given substance. In other words, different kinds of wave energy is produced by a 220 volt direct current quartz burner', some of which may be absorbed in a few inches of air, and some of which may be absorbed in but a minute nlm of the substance to be treated. Other wave energy from the same source may penetrate considerably deeper into the substance. Therefore,

i at a distance of one and one quarter inches from certain ray sources one will have some very ei- `fective wave energy available that is not available at a distance of several inches away. The particular medium or media and the condition thereof between the source and the portions of the substance to be treated also have a bearing on the eiectiveness of the ray energy which is available'ior use for the irradiation of the substance. We have discovered that a few or thousands of exposures to radiant energy of short wave lengths may be utilized to'produce benflcial eiTects in a substance when the time of each exposure is only a fraction Aof a second, as

. will be hereinafter described.

With our method of irradiation we are able to produce in milk a high degree of the vitamin D in the region of 2000 A, and 'notwithstanding it is stated by others that these short wave lengths are destructive rather than beneficial for vitamin D production.' ,We have found that these short wave lengths are only destructive to the vitamin D factor when used in a manner which does not provide for -their accurate control.

It will be noted that our method does not require the use of a 111m of the substance through which the rays will penetrate, although it may be advisable to irradiate with such a film if it can be produced. Ifone uses a film thicker than that through which the rays will penetrate, all of the energy entering the substance will be utilized,

while if a thin film is used a portion of the energyis wasted. It will be noted also that in our method the substance is agitated or'mixed after The mixing or agitating may be performed in any one of a number of ways although wehave found that the mixing accompanying the treatment of a substance during a plurality of passes through a single machine, or through a series of machines, as set forth in our pending application serial No. 418,027, now Patent No. 2,024,207, above nei'erred to, is sutilciently effective to accomplish satisfactory commercial results with many substances. -It wiii be understooafor exnmp1e,thot exposure. es is'done by those usine s 'thin nlm when we refer to thestep bf mixing in our methor thin stream or by those who agitate while od that this mixingmay'be accomplished by conunder the action of the rays. we only try to beneducting the substance to be treated through a ilcially irradiate a relatively small portion, or,

` bzfeonduit to andfrom the 'source' of treatment. Y you might say, the surface of the layer or lm 5 i In the irradiation of many substances, such as and then mix the substance while it is away from milk. we have learned that. it is highly desirable the action of the rays and thereafter return it for 'practica'l reasons .to`treat it in a moving yagain for treatment, repeating the cycle for as stream preferablyin the form' of a layer less many treatments as are necessary to give the rethan about onehalf inch in thickness. `But even suits desired. These repeated treatments are not 1o with a stream ofthis characterit is well known necessary or essential-*in the irradiation of .milk that er the most favorable conditions there is for the vitamin D effect since, as heretofore and cons tly taking place at least a-certain amount hereinafter pointed-out, we have found that with of incipient agitation or mixing of the various milk we can produce a substantial increase. in

l5 particles which go to make up the stream; The the vitamin D eifect with a single exposure for a 15 -amount of mixing would depend on lthe thickfreetiOn of e lee0nd ness of the layer, the distancethe stream runs We have discovered'tliat this cyclic method of Y sand'other flow conditions.V It is because of the livin! e Bubetl-nee freetioniolfleveil DIODefly recognition oi these facts that in dealing with e time short intermittent exposures (in plsee 0i one moving stream of liquid we have resorted t'o an continuous exposure) for .a liven number 0i 20 exposure or exposures or short duration, because times and mixing between exposures gives us exthe more the time of exposure is reduced the more cellent results. We have found that with a siven the Vmilk or. other liquid substance simulates a amount of active ray energy to'be applied t0 e body of liquid at rest in a container.. substance, Ithe amount of beneficial effect im- 21Sf l with respect to the irradiation of milk our inparted t0 s substance varies with the number of 25 vention is not necessarily limited to the productreatments given. We have also found that as tion of vitamin D potency in excess of that which 'a Idle. the number 0f treetmentl t0 'which e Subothers have heretofore attained but -rather is l stnee mey be sei'eiy subjected depende unen thev specifically directed, inter alla, to the production relation between the emOunt 0i treetment reof the vitamin D eect without detrimental efquired t0 deleteriously affect the substance. und 30 fects in an emcient manner by the novel process the minimi-lm melillt 'Oftietment n0988819 t0 of treating the vmilk by a-'single exposure while Fredi-lee l beneeil eieet in seid Bublteneeno substantial mixing takes place therein, and --the time 0i' eeeh exposure i8 t00 10118. 01' the this is contrary to all the teachings of the art. amount 0f treetment t0n met. then One ie By utilizing the principle of rst treating'free obliged to reduce the number of exposures in '35 from substantial mixing and then mixing the order to avoid detrimental eiteetl. end censetreated and untreated portions we are enabled to quently the amount of Vbeneficial eifects will be irradiate milk ofrthe usual degree of potency of less than if shorter exposures and more of them about 50 umts in only a fraction of the time were used.

40 required by others; or stated in another way, we According to the teachings herein, the time of 40 are enabled to irradiate many times the amount Aeach exposure. or-the amount of treatment given which others can irradiate ln` the same length during each exposure. may be 'readily predeterof time, everything else dbeing equal. mined by actually treating and; testing samples Iln using our process itis desirable to take into of the particular substance to be treated. Likeconsideration the intensity and wave lengths of wise, the`time intervals between'exposures mayl 45 the energy at all points in the field of action. be readily predetermined. 'Ihis is particularly Considering, for instance, the surface of the subimportant in steriiizing, because if the time instance being exposed, if we find the intensity tervais are too great it will enable bacteria to at one point of this surface to be lower thanv the recuperate from the eilects of any preceding exintensity at another point, or if the wave lengths v posure or exposures. We have found. as already 50 'are different at different points, it is evident stated, that the layer thickness used when'the that the rate of kilow should be faster where the substance is presented for irradiation has a beara high intensity or more powerful wavelengths exing on the number of exposures to be given and ist than where the low intensity or weaker wave the time of each exposure. We have also found 5r, lengths exist, to eifect a uniform treatment of that the degree of mixing given-between exposures 55 the surface during each exposure. Therefore. a will'also va'ry the results. Thorough mixing besimple method to control one element effecting the tween exposures gives the most accurate control amount of treatment given to a substance, is to of the amount of treatment and therefore tle work in a field of rays of uniform intensity having best results. However, this degree of mixing may 00 similar wave' lengths. The amount of treatment not be necessary in cases where the character of 00 received byparticles the same distance from the the substance does not require. it, or because` the Vsource will then be about the same for eachex maximum results are not desired. posure and once the characteristics of the sub- We offer below a possible explanation of our stance to be treatedare understood. the amount method which we have found to conformv closely of treatment received is a function of the time with data obtained from experiments with differe5 of exposure. The time of exposure forany part ent substances. y of a substance cannot be computed without a Suppose it is desired to irradiate to kill B. coil consideration of the particular wave lengths in a certain substance with ultra-violet ray treatavailable, as well as the intensity of said rays ment, which substance is susceptible of b eing at the point of utilization.v However. it will be detrimentally affected by such treatment and that 70 hereinafter seen that good results 'may be, obthese detrimental effects cannot be tolerated even tained' with our method evenv4 if the above dircin the slightest degree. Suppose further that a tions are not preciselyfoliowed. Inv a-general layer of the substance can be produced which way it can be said that instead of trying to irunder actual treatment with rays of a given inradiate the completer layer of a substance in one tensity and given wave length, shows a killing 75 effect of 50% of the bacteria in/ a l second exposure and we find that by a continuous exposure of seconds a detrimental effect is produced and a continuous exposure of 7% seconds does not cause v any detrimental eil'ect. This means that if 50% of the B. coli are killed in a l second exposure, that the active rays penetrated effectively one-half the depth of the layer. assuming. of/course, that the B. coli are evenly distributed.

This substance can be treated by exposing the same to said rays for seven 1 second exposures in a layer of the above mentioned thickness, and' mixing between exposures, and the result will be Y.

better than if a single exposure of 7 seconds were given. However, the total time of exposure in each case would be seven seconds, and less than the time necessary to cause a detrimental effect. We have foundby experiments that this step-bystep treatment o f giving several short exposures, with thorough mixings between-exposures, wi

give results approximately as follows:

Approximete total Number oi treatments v o' tht".

B. coli killed After ist treatment oi l second 50 After 2nd treatment ol l second 75 .After 3rd treatment of l second. 87 After 4th treatment of l second. 94 Alter 5th treatment of l second. 07 Alter lith treatment of l second.- .After 7th treatment oi l second 09 fects and get the maximum beneficial effect, one

should use a given time of exposure for each exposure, which time is dependent on the particular substance being treated. It has already been pointed out that thetime of each exposure, or, the amount of treatment given during each exposure, may be readily predetermined by actually treating and testing samples of the particular substance to be treated. The number of treat-l ments to be given, the time intervals between4 treatments', and therefore the accuracy of the control necessary, must likewise be predetermined. The best combinations of the time of exposure, or the amount of treatment, and the number of treatments in relation to the layer thickness, are also predetermined by actual trials. According to the teachings herein, itis relatively simple to test samples with a fair degree oi' accuracy and b. thus establish data by which our method may be practicedV in connection with any particular sub stance to be treated.

It will be seen that this substance containing B. coli is such that if one treats it seven times for one second each` time, some of the substance will receive seven seconds of exposure, but we have found that the amount of substance receiving a total of seven seconds of treatment is less with umane method which agitates the substance while under the action of the rays, and we, therefore, get a higher degree of beneficial effect with a greater safety factor. Itis seen from the above tablethat we can irradiate the substance with four exposures of one second each and realize about 94 per cent or more killing of B. coli, and this with a high safety factoragainst detrimental effects.

We have found vthat by using our ,method of I treatment and giving seven exposures'of one-'second each. as described above, that we irradiate only about one per cent of the substance for seven seconds, and consequently only a small portion has approached the -upper or danger limit. LNow, suppose we had treated the substance with-eight treatments of one` second each. According .tfo our original assumption an eight-second continuous exposure causes'detrimental effects. Now by our method eight one-second exposures would cause only about .5 per cent of the substance to be overexposed,`and in many cases this slight amount of over-treatment would be permissible and thus j eii'ect a greater percentage of killing than. could possibly be realized with one continuous exposure.

e Our method is such that opaque substances which cannot be reduced to a so-called thin layer or thin film can `be irradiated to a high degree of effectiveness. We have demonstrated this in experiments where we have sterilized milk to a safe degree in a layer thickness of inch. "It is generally known that a layer thickness of .0l of an inch is practically opaque to the active rays emanating from a source like 'that described herein and striking the surface of the milk. Therefore.

a inch layerA is at least thirty-seven times as,

to a high degree of safety without injuring the taste or odor. Further treatments reduced the bacteria count to zero. Y

We have also found from biological assays that milk similarly treated obtained a high degree of vitamin D effect with the 'number of exposures.

We have also irradiated milk lin a layer thickness of n5 of an inch for the purpose of producing vitamin D eHect. Twenty-five treatments or exposures of the milk in a layer of of an inch thickness.- where each exposure was for a fraction ,of a second. gave us a vitamin D content of about vone of'these experiments the vitamin D content produced was ten units per quart with one ex- We are not posure 1% 4inches from the ray source above de-` I scribed andina layer of milk of an inch thick over an area of about twenty square inches. When we yapplied our cyclic method and exposed eight times with short exposures of l/20th of a second each time. we obtain a substantial increase in the number of vitamin D units with each exwill eilectively penetrate. ,Now, if the substance is exposed a number Vof times and ior a certain fixed time during each exposure,only the undefined thinner layer proximate theray source, or approximately 10 per cent oi the total substance presented will be treated during each ex- I posure. If, after the irst exposure the substance is thoroughly mixed, the 10 per cent of the total substance which was treatedv during the rst exposure will be distributed evenly throughout the total amount of the substance and therefore one per cent of the total substance, or sth of the treated' substance will be distributed evenly through each of the' ten undefined layers, and when the substance is exposed a second time, 'another 10 per cent of the total substance will again be treated. The second exposure will treat 9 per cent of the substance for the ilrst time and retreat, so to speak, the 1 per cent that is distributed in the undefined layer proximate the ray source.

Hence, at the end of the second exposure a total f' of 19 per cent of the substance Awill have been treated, 4l per cent having been treated during both exposures, which vleaves 18 per cent. of the 'total substance having received one exposure.

This procedure can be carried on to any degree and thus we can reach a point where practically all of the substance is exposed at least once. After nine such exposures and mixings .0000001 per cent would be exposed 9 times .0000342 per cent would be exposed 8 times .0000777 per cent would be exposed 7 times .0067392 percent would be exposed 6 times .0802301 per cent would be exposed 5 times .7440095 per cent would be exposed 4 times 4.463883 per cent would be exposed 3 times 17.217365 per cent would be exposed 2 times 38.73916 per cent would be exposed once 38.7432 per cent would not be exposed at all.

This means that after nine exposures and thorough mixings between exposures about 61 per cent of the substance will be treated.

Now suppose a single one-second exposure of the layer produces 10 per cent of the possible bacteria killing eect in the total amount of the substances presented in the form of a layer, or per cent killing effect in the first of the ten undeilned thinner layers above referred to, and an exposure of less than one second caused a practically negligible killing effect. Suppose further that 10 seconds of continuous exposure produced an undesirable eilect on the substance, for example, changed its taste and odor, and nine seconds did not. Since nine treatments of one second each will not injure the substance it will be seen from the above that about 61 per cent oi the bacteriais killed without producing an undesirable effect therein.

Now suppose that we use an exposure of 1/2 second each time and expose for eighteen times.

'Ihis will cause about 85 per cent of the material to receive some exposure to the active rays and about 30 per cent of this would only receive one exposure of 54 second, leaving 55 per cent of exposed material which had been exposed between,`

1 and 9 seconds. Since. in the problem at hand, 1/2 second is not enough to produce a safe kill. ing effect, we have accomplished only a 55. per

cent killing edect in the substance by the combination of 18 exposures of 54 second-each. 'I'his is a lower percentage than we realized by 9 exposures of 1 second each. This, however, does not mean that exposures'oi less than 1/2 secondV wouldglve less than 55 per cent killing eifect, as will be explained below. y I

Now suppose we had.used exposures of 4% seconds each time.y 'Ihe killing effect will not be greater ony the proximate thinner layer because one cannot do more than kill all the bacteria. However, in this case we cannot expose more than twice without giving a total exposure of more than nine seconds. This combination would give us only 19 per cent killing effect, namely, 10 per cent for the iirst exposure and 9 per cent for the second exposure as stated above.

From this data it is clear that the duration of i treatment for each exposure and the number of exposures must be determined for any given substance to realize the benecial etl'ect desired. The' particular layer thickness used in the treatment has a bearing on the results that can be obtained becauseour method is not simply a matter of giving successive exposures but the time or amount of treatment received during each exposure must be considered. For example, we have shown that a variation oi' from 19 per cent to 61 per cent killing eil'ect could be obtained with a total exposure oi' 9 seconds by merely varying the time of each exposure yand the number of exposures. y9 seconds time of exposure is the limit oi' time specified in the example stated which must be considered to prevent detrimental effects.

We wish to call attention to the fact that in killing bacteria, in cases where one second of exposure will kill a germ and 1/2 second will not,

the use of two exposures of t second in some cases gives about the same eiect of killing as a single one-second exposure. 'I'his therefore perlliv mits the use of a single exposure of less than the .time required to produce the full effect and the appreciation of this fact' is advantageous in many applications of our method. We, however, wish to call attention to the fact that this minimum time of exposure probably has a limit beyond which we cannot go because the recuperative power of bacteria may'be too rapid for the destructive eifect oi' some short exposures, considering the elapsed time between exposures. This cumulative effect may also hold true in' regard to other effects, but we are not prepared to make a statement on this as yet. Ii several fractional exposures oi' short duration do 4not have a cumulative chemical or other eiect as is true of bacteria, this fact points the way ior using our method of bacteria destruction withoutcausing any chemical-eifect, namely, the use of exposures so short that their-'cumulative efect'does not cause a chemical change, and yet is long enough so that the cumulative -eil'ect will kill the utilization o! any residual effect ofirradiation and this may be another reason why we have obtained certain seemingly impossible results.

In practicing our method, we prefer to use apparatus such as, or similar to, that shown in our copending application above referred to, Serial No. 418.027, now Patent No. 2,024,207 and in our copending application Serial Number 567,574, filed October e, .1931, to which' applications reierence ls hereby made. By using apparatus'lof this character the process may readily be carried out, if desired, without substantial'exposure to atmospheric air which, inter alia. is not only desirable to avoid contamination of the substance being treated, but sometimes necessary as where the exposure to air of the substance being treated will cause chemical action to be set up in the substance or other deleterious effects to ensue.

In the foregoing description of our invention, it will be understood that when we mention vitamin D units or standard vitamin D umts, we are speaking ofsteenbock units.

Having particularly described our method of treatment, it will be apparent that the same is applicable vto the treatment of many substances not mentioned herein. Substances which are specincally mentioned, are referred to merely by way of example and without any intention of limiting ourselves to the treatment of only such substances. Our method of treatment may be used, therefore, in the treatment of manyother substances without departing from the spirit and scope o! our invention as dened by the appended claims.

40 amount of said treatment and which is also capable of having undesirable properties imparted thereto when said substance is exposed to a greater amount oi' said treatment, comprising treating a body of said substance at rest by exposing the 5 same to the influence of vsaid rays to impart beneficial properties to only a fractional portion or the substance forming said body, discontinuing said treatment when only said fractional portion of the body has been treated. mixing the treated portion of the substance forming said body with the untreated portion thereof while said treatment is discontinued. and thereafter alternately benecially treating fractional portions of said mixed body with said active rays as aforesaid, and mixing the substance aftereach treatment,

of treatment received during the exposures of said fractional portions is less than the time required to impart undesirable properties to any portion of said body.

2. The method of irradiating, while in a state capable of being mixed during said irradiation, a partially opaque substance which is also capable thereby of having beneficial and detrimental effects imparted thereto, which comprises exposing the substance'free from substantial mixing duringsuchexposureto the influenceof ultraviolet rays of sufllcient effectiveness and for such duration as to give to the same a fractional treatment and to impart beneficial eilects thereto but for a duration insumcient to impart undesirable eiects thereto, mixing said substance after such fractional treatment, and then alternately repeating these steps until the desired beneficial ef- .,5 fects throughout the substance have been atlas aforesaid, until the summation of the amounts' tained but less than that required to impart undesirable effects thereto.

3. 'Ihe method of antirachitically activating milk. which comprises exposing the milk free lfrom substantial mixing during such exposure to the inuence of ultra-violet rays oi suiilcient effectiveness -and for such duration as to give tothe 'same' a fractional treatment and to impart beneilcial eil'ects thereto but for a duration insumcient Ito impart undesirable detrimental eiects thereto,

mixing said milk after such fractional treatment, and then alternately repeating these steps until the desired beneficial effects throughout the milk have been attained butless than that required to impart undesirable detrimental effects thereto.

4. The method of treating milk by means of ultra-violet rays. which comprises conveying the milk in a moving stream of greater thickness than that through which' the rays will penetrate, exposing said moving stream to the influence of said rays of sumcient eifectiveness and for such duration as to give to the same a fractional treatment and to impart beneficial effects thereto, but insuilicient to impart undesirable effects thereto, the duration being also sumciently short and operating conditions such that no substantial mixing takes place during such exposure. mixing said milk after such fractional treatment, and

then alternately repeating these steps until the l desired benecial effects throughout the milk have been attained but less than that required to impart undesirable eiects thereto.

5. The method of irradiating liquid milk to l produce the vitamin D effect and any other benealso capable oi' having benecial eil'ects and detrimental efiectsjimparted thereto, which comprises exposing said substance a predetermined number of times free from substantial mixing during each exposure andat a predetermined temperature to a predetermined amount of ultra-violet ray energy whilst mixing said substance between exposures.

7. The method of irradiating milk'to produce a high percentage of a vitamin D effect and other benecial effects therein and without imparting any undesirable detrimental effects thereto, which comprises conveying the milk in a moving layer or sheet of uniform thickness but of greater thickness than that through which the rays will effectively penetrate, and exposing said layer or sheet of milk successively at a predetermined number of stages free from substantial'mixing during each exposure to a predetermined amount of ultra-violet rayenergy whilst mixing the layer or sheet of milk for predetermined time intervals between stages.

8. The method of irradiating a partially opaque substance, capable of being mixed during said irradiation to produce beneficial eiects therein and without imparting undesirable eil'ects thereto, which comprises conveying the substance in a moving stream, intermittently exposing the substance to a beneficially effective amount of ultramoving stream, the duration Vof each exposure being sufficiently short and operating conditions such that no substantial mixing takes place duringsuchexposureandthedurationofsuch elimination being sumciently longto enable substantial mixing of the substance between exposures,

and the summation of the amounts of treatment 'receivedduringsuchexposuresbeinglessthan the time required to impart undesirable properties to any portion of said substance.

10. The method of irradiating, while in a state capable of being mixed during said irradiation a partially opaque vsubstance which is also capable thereby of'having beneficial and detrimental effects imparted thereto, which comprises exposing in the absence of air the substance free from substantial mixing during such exposure to the influence of ultra-violet rays of vsufllcientefi'ectiveness and for such duration as to give to the same a fractional treatment and to impart bene- Lilcial effects thereto but for a duration insumcient to impart undesirable effects thereto, mixing' said substance after such fractional treati ment, and then alternately repeating these steps until the desired beneficial effects throughout 40 the substance,have been attained but less than that required to impart undesirable effects there- 11. The method of irradiating a partially opaque substance,'capable of being mixed during 45 said irradiation to produce beneficial effects therein and without imparting undesirable effects thereto, which comprises conveying the substance in the absence of air in a moving stream through a closed container, intermittently exposing the 50 substance while in the container toy a benecially effective amount of ultra-violet ray energy, the.

duration of each exposure being suiiiciently short and operating conditions such that no substan-` tial mixing takes place during such exposure, and 55 mixing the substance between exposures.

12. A method for the irradiation by ultra-violet rays of a partially opaque liquid in which more or less 'agitation or mixing is constantly taking place and which is also capable of having bene- 60 ilcial and detrimental effects imparted thereto, which comprises forcing the liquid in a conned relatively thin layer through treating zones of a closed container and in a confined relatively thick layer through mixing zones of said con- 65 tainer, treating said thin layers with ultra-violet rays in such a manner that only the portion of said relatively thin layer proximate the source of said ultra-violet rays is exposed for a time necessary to produce a benecial effect but for less 70 time than would cause a detrimental effect in said proximate portion and substantially no eifect in the remote portion of said thin layer whereby no substantial mixing takes place during each treatment, and between successive treat- 7c in! mi!! mixing in said mixing sones said treated 9 pomohofmatmnlmnwithmumhus portion thereof.

13. 'nie method of antirachitically activating milk by means of ultra-violet rays kwithout 'imparting undesirable detrimental eil'ects thereto. which comprises .the steps of conveying the milk in a moving layer thicker than that through which the rays will enectively penetrate during such movement, and, during suchlnovement, exposing the portion of said layer proximate the ray source to a beneficially effective amount of ultra violet ray energy, said layer being of such thickness as to enable the treatment of such a fraction thereof that the desired potency is obtained in the total volume of milk conveyed when said proximate beneficially affected portion is mixed with the remote portion thereof, and the duration of such exposure being suiliciently short and operating conditions such that no substantial mixing takes place during such exposure, and. thereafter mixing the beneficially affected and remote portions of said milk. 1

14. The method of antirachitically activating milk by means of ultra-violet rays without imparting undesirable detrimental eifects thereto, which comprises the steps of conveying the `milk in a moving layer thicker than that through which the rays will effectively penetrate during such movement, and, during such movement, exposing said layer proximate the ray source to a beneficially effective amount of ultra-violet ray energy for only a fraction of a second and with operating conditions such that no substantial mixing takes place during such exposure. said layer being suilciently thin to enable such a fraction thereof to be beneficially treated which, when mixed with the remote portion thereof, the desired potency is obtained in the total volume of milk conveyed, and thereafter mixing the treated' with the untreated portions of said milk.

15. 'I'he method of antirachitically activating milk by means of ultra-violet rays without irnparting undesirable detrimental effects thereto, which comprises the steps of conveying the milk in a moving layer thicker than that through which the rays will effectively penetrate during such movement, and, during such movement, exposing the portion of 'said layer proximate the ray source to a beneficially effective amount of ultra-violet ray energy, in the absence of air, said' layer being of such thickness as to enable the treatment; of such a' fraction thereof that the desired potency is obtained in the total volume oi' milk conveyed when said proximate beneficially affected portion is mixed with the remote portion thereof, and the duration of such'exposure being suiiiciently short and 'operating conditions such that no substantial mixing takes place during such exposure, and thereafter mixing the beneflcially treatedl and remote portions of the milk.

16. The method of irradiating milk with ultraviolet rays to produce the vitamin D eiect therein and without imparting undesirable eiects thereto while owing said milk in a layer thicker than that through which the rays will effectively penetrate during the irradiation period to ultimately produce in the whole layer of said milk conveyed a beneficial eect without causing undesirable detrimental efl'ects therein, characterized by the steps of flowing said milk through a field irradiated by ultra violet rays of such in'- tenslty and with flow conditionssuch that during the period of irradiation necessary to cause a ben- ,not substantially mixed and thereafter mixing g ing undesirable eects thereto. which comprises the steps oi conveying ythis milk in a moving stream thicker than that through which the rays will eflectively penetrate. exposingthe milk during such movement to a beneficially elective amount oi' ultra-violet ray energy, the duration o! such exposure being suiilciently short and operating conditions such that no substantial' mixing takes place during such exposure. and therealter mixing the exposed with the unexposed por- `capable oi.' being mixed during said irradiation,

a partially opaque substance also capable otA having beneficial effects and undesirable detrimental effects imparted thereto which comprises. `ex posing the substance free from substantial mixing during such exposure to a predetermined amount of ultra-violet ray energy, thereafter mix- Patent No. 2,072,416.

15 tions of said milk. v ing said substance. and then alternately repeating 18. The method of irradiating milk to produce these steps at predetermined time intervals until the vitamin` D eiiect therein and without impartthe desired beneficial eiects throughout the subing any undesirable detrimental effects thereto. stance have been attained. which comprises the steps of conveying the milk I zo in a moving stream thicker than that through EDWARD C. BERNDT.

which the rays will eilectively penetrate. expos- HARRY M. CREIGHTON.

CERTIFICATE OF CORRECTION.

March 2, 1937.

EDWARD C. BERNDT, ET AL.,

It is hereby certified that error appears in the printed specification of the above numberedv patent requiring correction as follows: Page l. second column, line 49, strike out the words "irradiating a substance wherein maximum" and insert the words active ray energy is utilized to produce the; page 4, column 2, line l for "use" read used; page 5, second column, line 19, for "time" read timed; page 8, second column, line 7l claim 8, after "irradiation" insert a comma; and that the said Letters Patent should be read with these correctionsl therein that the same may conform to the `record of the case in the Patent Office. Y'

Signed and sealed this 8th day of June, A'. D. .1937.

(Seal)v Henry Van Arsdale AActing Commissioner of Patents.

v, Disclaimer v 2,072,416.Edword 0. Berndt, Norwalk, and Harry M. Creighton, East Norwalk,

Mn'raoo or Ianni-.unimo SUns'rsNcss Wrrs Ac'rxvl: Rus.

Patent dated Mar. 2, 1937. yDisclaimer filed Dec. 8, 1948, by the assignee, The

R. U. V. Engineering Corporation. Hereby [Ovdl Goutte January 4, 1949,]

enters this disclaimer to claims i3 to 18 inclusive of said patent.

g ing undesirable eects thereto. which comprises the steps oi conveying ythis milk in a moving stream thicker than that through which the rays will eflectively penetrate. exposingthe milk during such movement to a beneficially elective amount oi' ultra-violet ray energy, the duration o! such exposure being suiilciently short and operating conditions such that no substantial' mixing takes place during such exposure. and therealter mixing the exposed with the unexposed por- `capable oi.' being mixed during said irradiation,

a partially opaque substance also capable otA having beneficial effects and undesirable detrimental effects imparted thereto which comprises. `ex posing the substance free from substantial mixing during such exposure to a predetermined amount of ultra-violet ray energy, thereafter mix- Patent No. 2,072,416.

15 tions of said milk. v ing said substance. and then alternately repeating 18. The method of irradiating milk to produce these steps at predetermined time intervals until the vitamin` D eiiect therein and without impartthe desired beneficial eiects throughout the subing any undesirable detrimental effects thereto. stance have been attained. which comprises the steps of conveying the milk I zo in a moving stream thicker than that through EDWARD C. BERNDT.

which the rays will eilectively penetrate. expos- HARRY M. CREIGHTON.

CERTIFICATE OF CORRECTION.

March 2, 1937.

EDWARD C. BERNDT, ET AL.,

It is hereby certified that error appears in the printed specification of the above numberedv patent requiring correction as follows: Page l. second column, line 49, strike out the words "irradiating a substance wherein maximum" and insert the words active ray energy is utilized to produce the; page 4, column 2, line l for "use" read used; page 5, second column, line 19, for "time" read timed; page 8, second column, line 7l claim 8, after "irradiation" insert a comma; and that the said Letters Patent should be read with these correctionsl therein that the same may conform to the `record of the case in the Patent Office. Y'

Signed and sealed this 8th day of June, A'. D. .1937.

(Seal)v Henry Van Arsdale AActing Commissioner of Patents.

v, Disclaimer v 2,072,416.Edword 0. Berndt, Norwalk, and Harry M. Creighton, East Norwalk,

Mn'raoo or Ianni-.unimo SUns'rsNcss Wrrs Ac'rxvl: Rus.

Patent dated Mar. 2, 1937. yDisclaimer filed Dec. 8, 1948, by the assignee, The

R. U. V. Engineering Corporation. Hereby [Ovdl Goutte January 4, 1949,]

enters this disclaimer to claims i3 to 18 inclusive of said patent. 

